Parking assist system

ABSTRACT

A parking assist system includes an acquiring unit, a display unit, and a control unit. In a case where the acquiring unit acquires information about an obstacle on a first target route during traveling of a vehicle along the first target route and thus the vehicle stops traveling along the first target route, the control unit tries to calculate a second target route to a target position from a position where the vehicle stops traveling along the first target route. Upon succeeding in calculating the second target route, the control unit causes the display unit to display surrounding information corresponding to the second target route. Upon failing to calculate the second target route, the control unit causes the display unit to display a notification about an operation method of the vehicle.

TECHNICAL FIELD

The present invention relates to a parking assist system.

BACKGROUND ART

Conventionally, there is a parking assist system configured to executeautomatic parking for autonomously moving a vehicle to a targetposition. For example, such a parking assist system includes anacquiring unit configured to acquire surrounding information aboutsurroundings of the vehicle and a control unit configured to calculate atarget route of the vehicle and to cause the vehicle to travel along thetarget route.

For example, JP2020-11559A discloses a vehicle control device includingan environment recognizing device configured to acquire informationabout an environment around an own vehicle, a route generating unitconfigured to generate a parking route for moving the own vehicle from acurrent position to a target parking position, and a vehicle controlunit configured to control the own vehicle along the parking routegenerated by the route generating unit.

In the parking assist system as described above, the acquiring unit mayacquire information about an obstacle on the target route while thevehicle is traveling along the target route, and thus the vehicle maystop traveling along the target route before reaching the targetposition. In such a case, the parking assist system is required toappropriately notify the user of the behavior of the vehicle aftertraveling of the vehicle along the target route is stopped.

SUMMARY OF THE INVENTION

In view of such a problem of the prior art, a primary object of thepresent invention is to provide a parking assist system that canappropriately notify the user of the behavior of the vehicle in a casewhere the vehicle stops traveling along the target route due to thepresence of the obstacle.

To achieve such an object, one embodiment of the present inventionprovides a parking assist system (1) configured to execute automaticparking for autonomously moving a vehicle to a target position, theparking assist system including: an acquiring unit (7) configured toacquire surrounding information about surroundings of the vehicle; adisplay unit (32) configured to display the surrounding informationacquired by the acquiring unit; and a control unit (15) configured tocalculate a first target route to the target position based on thesurrounding information acquired by the acquiring unit and to cause thevehicle to travel along the first target route, wherein in a case wherethe acquiring unit acquires information about an obstacle on the firsttarget route during traveling of the vehicle along the first targetroute and thus the vehicle stops traveling along the first target route,the control unit tries to calculate a second target route to the targetposition from a position where the vehicle stops traveling along thefirst target route, upon succeeding in calculating the second targetroute, the control unit causes the display unit to display thesurrounding information corresponding to the second target route, andupon failing to calculate the second target route, the control unitcauses the display unit to display a notification (51) about anoperation method of the vehicle.

According to this arrangement, in a case where the vehicle stopstraveling along the first target route due to the presence of theobstacle, the display unit can selectively display either thesurrounding information or the notification about the operation methodof the vehicle depending on the success or failure of the calculation ofthe second target route. Accordingly, it is possible to appropriatelynotify the user of the behavior of the vehicle.

In the above arrangement, preferably, the display unit is configured todisplay a traveling direction image as the surrounding information, thetraveling direction image being an image in a traveling direction of thevehicle, and upon succeeding in calculating the second target route, thecontrol unit causes the display unit to display the traveling directionimage in a direction opposite to the traveling direction of the vehicleimmediately before the vehicle stops traveling along the first targetroute.

When the vehicle starts traveling along the second target route afterstopping traveling along the first target route, the traveling directionof the vehicle is switched in order to move the vehicle away from theobstacle on the first target route. According to the above arrangement,the display unit can display an appropriate traveling direction image inconsideration of the above switch in the traveling direction of thevehicle. Accordingly, it is possible to prompt the user to monitor thesurroundings of the vehicle, and to improve the safety of the vehicle.

In the above arrangement, preferably, upon succeeding in calculating thesecond target route, the control unit causes the vehicle to starttraveling along the second target route regardless of whether a user hasperformed a brake operation of the vehicle.

According to this arrangement, it is possible to cause the vehicle tostart traveling along the second target route without causing the userto perform the brake operation of the vehicle. Accordingly, it ispossible to improve the convenience of the user.

In the above arrangement, preferably, upon succeeding in calculating thesecond target route, the control unit causes the vehicle to starttraveling along the second target route at least on condition that auser performs a brake operation of the vehicle.

According to this arrangement, it is possible to cause the vehicle tostart traveling along the second target route after the user performsthe brake operation of the vehicle. Accordingly, the user can easilypredict that the vehicle will travel along the second target route.

In the above arrangement, preferably, upon failing to calculate thesecond target route, the control unit makes a determination as to aperformance state of a brake operation of the vehicle by a user.

According to this arrangement, upon failing to calculate the secondtarget route, the control unit can perform appropriate control accordingto the performance state of the brake operation of the vehicle by theuser. Accordingly, it is possible to improve the safety of the vehicle.

In the above arrangement, preferably, upon failing to calculate thesecond target route, the control unit causes the display unit to displaya promotion notification (51) as the notification about the operationmethod of the vehicle, the promotion notification promoting the brakeoperation of the vehicle.

According to this arrangement, it is possible to improve the safety ofthe vehicle by promoting the brake operation of the vehicle by the user.

In the above arrangement, preferably, upon failing to calculate thesecond target route, the control unit determines whether anon-performance period during which the user does not perform the brakeoperation of the vehicle continues for a prescribed period or more, andupon determining that the non-performance period continues for theprescribed period or more, the control unit causes the display unit todisplay the promotion notification.

In a case where the non-performance period continues for the prescribedperiod or more, the user may not be monitoring the surroundings of thevehicle even though the obstacle is present on the first target route.According to the above arrangement, it is possible to further improvethe safety of the vehicle by promoting the brake operation of thevehicle by the user in consideration of the possibility of such asituation. Further, the promotion notification is displayed on conditionthat the non-performance period continues for the prescribed period ormore (namely, the user does not perform the brake operation for theprescribed period or more), thereby preventing the promotionnotification from being displayed at an excessively early timing afterthe user stops performing the brake operation. Accordingly, it ispossible to prevent the user from being annoyed.

In the above arrangement, preferably, in a case where the user performsthe brake operation of the vehicle in response to the promotionnotification, the control unit causes the display unit to display aresumption selection notification (53) in which the user can selectresumption of the automatic parking.

According to this arrangement, in a case where the user performs thebrake operation of the vehicle in response to the promotionnotification, it is possible to cause the user to select whether toresume the automatic parking by displaying the resumption selectionnotification. Accordingly, it is possible to resume the automaticparking based on the user's intention, thereby improving the safety ofthe vehicle.

In the above arrangement, preferably, upon failing to calculate thesecond target route, the control unit determines whether anon-performance period during which a user does not perform a brakeoperation of the vehicle continues for a prescribed period or more, andin a case where the control unit determines that the non-performanceperiod does not continue for the prescribed period or more and theacquiring unit stops acquiring the information about the obstacle on thefirst target route, the control unit resumes the automatic parking atleast on condition that the user stops performing the brake operation ofthe vehicle.

According to this arrangement, in a case where the obstacle is no longerpresent on the first target route and the user stops performing thebrake operation of the vehicle, it is possible to resume the automaticparking without resetting the target route. Accordingly, it is possibleto improve the convenience of the user.

Thus, according to the above arrangements, it is possible to provide aparking assist system that can appropriately notify the user of thebehavior of the vehicle in a case where the vehicle stops travelingalong the target route due to the presence of the obstacle.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a functional block diagram of a vehicle provided with aparking assist system according to an embodiment of the presentinvention;

FIG. 2 is a flowchart of an automatic parking process in the parkingassist system according to the embodiment;

FIG. 3A is a diagram showing a screen display of a touch panel during atarget parking position reception process in the parking assist systemaccording to the embodiment;

FIG. 3B is a diagram showing the screen display of the touch panelduring a driving process in the parking assist system according to theembodiment;

FIG. 3C is a diagram showing the screen display of the touch panel whenautomatic parking is completed in the parking assist system according tothe embodiment;

FIG. 4 is a flowchart showing the driving process in the parking assistsystem according to the embodiment;

FIG. 5A is a diagram showing a promotion screen in the parking assistsystem according to the embodiment;

FIG. 5B is a diagram showing a resumption notification screen in theparking assist system according to the embodiment;

FIG. 5C is a diagram showing a resumption selection screen in theparking assist system according to the embodiment;

FIG. 6 is a flowchart showing a display process in the parking assistsystem according to the embodiment; and

FIG. 7 is a flowchart showing a display process in a parking assistsystem according to another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In the following, an embodiment of the present invention will bedescribed in detail with reference to the drawings.

A parking assist system 1 is mounted on a vehicle such as an automobileprovided with a vehicle control system 2 configured to make the vehicletravel autonomously.

As shown in FIG. 1, the vehicle control system 2 includes a powertrain4, a brake device 5, a steering device 6, an external environment sensor7, a vehicle sensor 8, a navigation device 10, an operation input member11, a driving operation sensor 12, a state detecting sensor 13, a humanmachine interface (HMI) 14, and a control device 15. The abovecomponents of the vehicle control system 2 are connected to each otherso that signals can be transmitted therebetween via communication meanssuch as a Controller Area Network (CAN).

The powertrain 4 is a device configured to apply a driving force to thevehicle. The powertrain 4 includes a power source and a transmission,for example. The power source includes at least one of an internalcombustion engine, such as a gasoline engine and a diesel engine, and anelectric motor. In the present embodiment, the powertrain 4 includes anautomatic transmission 16 and a shift actuator 17 for changing a shiftposition of the automatic transmission 16 (a shift position of thevehicle). The brake device 5 is a device configured to apply a brakeforce to the vehicle. For example, the brake device 5 includes a brakecaliper configured to press a brake pad against a brake rotor and anelectric cylinder configured to supply a brake pressure (an oilpressure) to the brake caliper. The brake device 5 may include anelectric parking brake device configured to restrict rotations of wheelsvia wire cables. The steering device 6 is a device for changing asteering angle of the wheels. For example, the steering device 6includes a rack-and-pinion mechanism configured to steer (turn) thewheels and an electric motor configured to drive the rack-and-pinionmechanism. The powertrain 4, the brake device 5, and the steering device6 are controlled by the control device 15.

The external environment sensor 7 serves as an external surroundinginformation acquisition device for detecting electromagnetic waves,sound waves, and the like from the surroundings of the vehicle to detectan object outside the vehicle and to acquire surrounding information ofthe vehicle. The external environment sensor 7 includes sonars 18 andexternal cameras 19. The external environment sensor 7 may furtherinclude a millimeter wave radar and/or a laser lidar. The externalenvironment sensor 7 outputs a detection result to the control device15.

Each sonar 18 consists of a so-called ultrasonic sensor. Each sonar 18emits ultrasonic waves to the surroundings of the vehicle and capturesthe ultrasonic waves reflected by an object, thereby detecting theposition (distance and direction) of the object. Plural sonars 18 areprovided at each of a rear portion and a front portion of the vehicle.In the present embodiment, a pair of sonars 18 are provided on a rearbumper so as to be spaced laterally from each other, a pair of sonars 18are provided on a front bumper so as to be spaced laterally from eachother, and four sonars 18 are provided at front and rear ends of bothlateral surfaces of the vehicle, respectively. Namely, the vehicle isprovided with eight sonars 18 in total. The sonars 18 provided on therear bumper mainly detect the positions of the objects behind thevehicle. The sonars 18 provided on the front bumper mainly detect thepositions of the objects in front of the vehicle. The sonars 18 providedat the front ends of both lateral surfaces of the vehicle detect thepositions of the objects on left and right outsides of the front end ofthe vehicle, respectively. The sonars 18 provided at the rear ends ofboth lateral surfaces of the vehicle detect the positions of the objectson left and right outsides of the rear end of the vehicle, respectively.

The external cameras 19 are devices configured to capture images aroundthe vehicle. Each external camera 19 consists of a digital camera usinga solid imaging element such as a CCD or a CMOS, for example. Theexternal cameras 19 include a front camera for capturing an image infront of the vehicle and a rear camera for capturing an image to therear of the vehicle. The external cameras 19 may include a pair of leftand right side cameras that are provided in the vicinity of the doormirrors of the vehicle to capture images on left and right sides of thevehicle.

The vehicle sensor 8 includes a vehicle speed sensor configured todetect the vehicle speed of the vehicle, an acceleration sensorconfigured to detect the acceleration of the vehicle, a yaw rate sensorconfigured to detect the angular velocity around a vertical axis of thevehicle, and a direction sensor configured to detect the direction ofthe vehicle. For example, the vehicle speed sensor consists of pluralwheel speed sensors. Each wheel speed sensor is configured to detect thewheel speed (the rotational speed of each wheel). For example, the yawrate sensor consists of a gyro sensor.

The navigation device 10 is a device configured to obtain a currentposition of the vehicle and provides route guidance to a destination andthe like. The navigation device 10 includes a GPS receiving unit 20 anda map storage unit 21. The GPS receiving unit 20 identifies a position(latitude and longitude) of the vehicle based on a signal received froman artificial satellite (positioning satellite). The map storage unit 21consists of a known storage device such as a flash memory or a harddisk, and stores map information.

The operation input member 11 is provided in a vehicle cabin to receivean input operation performed by the occupant (user) to control thevehicle. The operation input member 11 includes a steering wheel 22, anaccelerator pedal 23, a brake pedal 24 (brake input member), and a shiftlever 25 (shift member). The shift lever 25 is configured to receive anoperation for switching the shift position of the vehicle.

The driving operation sensor 12 detects an operation amount of theoperation input member 11. The driving operation sensor 12 includes asteering angle sensor 26 configured to detect a turning angle of thesteering wheel 22, a brake sensor 27 configured to detect a pressingamount of the brake pedal 24, and an accelerator sensor 28 configured todetect a pressing amount of the accelerator pedal 23. The drivingoperation sensor 12 outputs a detected operation amount to the controldevice 15.

The state detecting sensor 13 is a sensor configured to detect a changein a state of the vehicle according to an operation by the occupant. Theoperation by the occupant detected by the state detecting sensor 13includes an operation indicating an alighting intention (intention toalight from the vehicle) of the occupant and an operation indicatingabsence of an intention of the occupant to check the surroundings of thevehicle during an autonomous parking operation or an autonomousunparking operation. The state detecting sensor 13 includes, as sensorsfor detecting the operation indicating the alighting intention, a dooropen/close sensor 29 configured to detect opening and/or closing of adoor of the vehicle and a seat belt sensor 30 configured to detect afastening state of a seat belt. The state detecting sensor 13 includes,as a sensor to detect the operation corresponding to the abdicatingintention, a door mirror position sensor 31 configured to detect aposition of a door mirror. The state detecting sensor 13 outputs asignal indicating a detected change in the state of the vehicle to thecontrol device 15.

The HMI 14 is an input/output device for receiving an input operation bythe occupant and notifying the occupant of various kinds of informationby display and/or voice. The HMI 14 includes, for example, a touch panel32 that includes a display screen such as a liquid crystal display or anorganic EL display and is configured to receive the input operation bythe occupant, a sound generating device 33 such as a buzzer or aspeaker, a parking main switch 34, and a selection input member 35. Theparking main switch 34 receives the input operation by the occupant toexecute selected one of an automatic parking process (autonomous parkingoperation) and an automatic unparking process (autonomous unparkingoperation). The parking main switch 34 is a so-called momentary switchthat is turned on only while a pressing operation (pushing operation) isperformed by the occupant. The selection input member 35 receives aselection operation by the occupant related to selection of theautomatic parking process and the automatic unparking process. Theselection input member 35 may consist of a rotary select switch, whichpreferably requires pressing as the selection operation.

The control device 15 consists of an electronic control unit (ECU) thatincludes a CPU, a nonvolatile memory such as a ROM, a volatile memorysuch as a RAM, and the like. The CPU executes operation processingaccording to a program so that the control device 15 executes varioustypes of vehicle control. The control device 15 may consist of one pieceof hardware, or may consist of a unit including multiple pieces ofhardware. Further, the functions of the control device 15 may be atleast partially executed by hardware such as an LSI, an ASIC, and anFPGA, or may be executed by a combination of software and hardware.

Further, the control device 15 executes an arithmetic process accordingto a program and thereby performs a conversion process of an image(video) captured by the external cameras 19 so as to generate alook-down image corresponding to a plan view of the vehicle and itssurrounding area and a bird's-eye image corresponding to athree-dimensional image of the vehicle and a part of its surroundingarea positioned in the traveling direction as viewed from above. Thecontrol device 15 may generate the look-down image by combining theimages of the front camera, the rear camera, and the left and right sidecameras, and may generate the bird's-eye image by combining the imagecaptured by the front camera or the rear camera facing the travelingdirection and the images captured by the left and right side cameras.

The parking assist system 1 is a system for executing the so-calledautomatic parking process and the so-called automatic unparking process,in which a vehicle is moved autonomously to a prescribed target position(a target parking position or a target unparking position) selected bythe occupant so as to park or unpark the vehicle.

The parking assist system 1 includes the external environment sensor 7(an example of an acquiring unit) configured to acquire an image in thetraveling direction of the vehicle and information about an obstacle (anexample of surrounding information about surroundings of the vehicle),the touch panel 32 (an example of a display unit) configured to displaythe image in the traveling direction of the vehicle acquired by theexternal environment sensor 7, and the control device 15 (an example ofa control unit) configured to calculate a trajectory of the vehicle tothe target position based on the information about the obstacle acquiredby the external environment sensor 7 and to cause the vehicle to travelalong the calculated trajectory.

The control device 15 controls the powertrain 4, the brake device 5, andthe steering device 6 so as to execute an autonomous parking operationto move the vehicle autonomously to a target parking position and parkthe vehicle at the target parking position and an autonomous unparkingoperation to move the vehicle autonomously to a target unparkingposition and unpark the vehicle at the target unparking position. Inorder to execute such operations, the control device 15 includes anexternal environment recognizing unit 41, a vehicle position identifyingunit 42, an action plan unit 43, a travel control unit 44, a vehicleabnormality detecting unit 45, and a vehicle state determining unit 46.

The external environment recognizing unit 41 recognizes an obstacle (forexample, a parked vehicle or a wall) that is present around the vehiclebased on the detection result of the external environment sensor 7, andthereby obtains information about the obstacle. Further, the externalenvironment recognizing unit 41 analyzes the images captured by theexternal cameras 19 based on a known image analysis method such aspattern matching, and thereby determines whether a vehicle stopper(wheel stopper) or an obstacle is present, and obtains the size of thevehicle stopper or the obstacle in a case where the vehicle stopper orthe obstacle is present. Further, the external environment recognizingunit 41 may compute a distance to the obstacle based on signals from thesonars 18 to obtain the position of the obstacle.

Also, by the analysis of the detection result of the externalenvironment sensor 7 (more specifically, by the analysis of the imagescaptured by the external cameras 19 based on a known image analysismethod such as pattern matching), the external environment recognizingunit 41 can acquire, for example, a lane on a road delimited by roadsigns and a parking space delimited by white lines and the like providedon a surface of a road, a parking lot, and the like.

The vehicle position identifying unit 42 identifies the position of thevehicle (the own vehicle) based on a signal from the GPS receiving unit20 of the navigation device 10. Further, the vehicle positionidentifying unit 42 may obtain the vehicle speed and the yaw rate fromthe vehicle sensor 8, in addition to the signal from the GPS receivingunit 20, and identify the position and posture of the vehicle by theso-called inertial navigation.

The travel control unit 44 controls the powertrain 4, the brake device5, and the steering device 6 based on a travel control instruction fromthe action plan unit 43 to make the vehicle travel.

The vehicle abnormality detecting unit 45 detects an abnormality of thevehicle (hereinafter referred to as “vehicle abnormality”) based onsignals from various devices and sensors. The vehicle abnormalitydetected by the vehicle abnormality detecting unit 45 includes failureof various devices necessary for driving the vehicle (for example, thepowertrain 4, the brake device 5, and the steering device 6) and failureof various sensors necessary for making the vehicle travel autonomously(for example, the external environment sensor 7, the vehicle sensor 8,and the GPS receiving unit 20). Further, the vehicle abnormalityincludes failure of the HMI 14.

The vehicle state determining unit 46 acquires the state of the vehiclebased on signals from various sensors provided in the vehicle, anddetermines whether the vehicle is in a prohibition state in which theautonomous movement (namely, the autonomous parking operation or theautonomous unparking operation) of the vehicle should be prohibited. Thevehicle state determining unit 46 determines that the vehicle is in theprohibition state when the occupant performs a driving operation(override operation) of the operation input member 11. The overrideoperation is an operation to override (cancel) the autonomous movement(namely, the autonomous parking operation or the autonomous unparkingoperation) of the vehicle.

Further, the vehicle state determining unit 46 determines, based on thedetection result of the state detecting sensor 13, that the vehicle isin the prohibition state when the vehicle is in a state that reflectsthe alighting intention (intention to alight from the vehicle) of theoccupant. More specifically, when the door open/close sensor 29 detectsthat the door is opened, the vehicle state determining unit 46determines that the vehicle is in the prohibition state. Also, when theseat belt sensor 30 detects that the seat belt is released, the vehiclestate determining unit 46 determines that the vehicle is in theprohibition state.

Further, the vehicle state determining unit 46 determines, based on thedetection result of the state detecting sensor 13, that the vehicle isin the prohibition state when the vehicle is in a state that reflectsthe absence of intention of the occupant to check the surroundings ofthe vehicle. More specifically, the vehicle state determining unit 46determines that the vehicle is in the prohibition state when the doormirror position sensor 31 detects that the door mirror is retracted.

The action plan unit 43 executes the automatic parking process(autonomous parking operation) or the automatic unparking process(autonomous unparking operation) when the vehicle is in a prescribedstate and the HMI 14 or the parking main switch 34 receives a prescribedinput by the user, which corresponds to a request for the automaticparking process or the automatic unparking process. More specifically,the action plan unit 43 executes the automatic parking process in a casewhere a prescribed input corresponding to the automatic parking processis performed when the vehicle is stopped or the vehicle is traveling ata low speed equal to or less than a prescribed vehicle speed (a vehiclespeed at which a parking position candidate can be searched for). Theaction plan unit 43 executes the automatic unparking process (parallelunparking process) in a case where a prescribed input corresponding tothe automatic unparking process is performed when the vehicle isstopped. The selection of the process to be executed (the automaticparking process or the automatic unparking process) may be made by theaction plan unit 43 based on the state of the vehicle. Alternatively,the above selection may be made by the occupant via the touch panel 32or the selection input member 35. When executing the automatic parkingprocess, the action plan unit 43 first makes the touch panel 32 displaya parking search screen for setting the target parking position. Afterthe target parking position is set, the action plan unit 43 makes thetouch panel 32 display a parking screen. When executing the automaticunparking process, the action plan unit 43 first makes the touch panel32 display an unparking search screen for setting the target unparkingposition. After the target unparking position is set, the action planunit 43 makes the touch panel 32 display an unparking screen.

In the following, the automatic parking process will be described withreference to FIG. 2. The action plan unit 43 first executes anacquisition process (step ST1) to acquire one or more parking spaces, ifany. More specifically, in a case where the vehicle is stopped, theaction plan unit 43 first makes the touch panel 32 of the HMI 14 displaya notification that instructs the occupant to move the vehicle straight.While the occupant sitting in the driver's seat (hereinafter referred toas “driver”) is moving the vehicle straight, the external environmentrecognizing unit 41 acquires, based on a signal from the externalenvironment sensor 7, a position and size of each detected obstacle andpositions of the white lines provided on the road surface. The externalenvironment recognizing unit 41 extracts, based on the acquired positionand size of the obstacle and the acquired positions of the white lines,one or more undelimited parking spaces and one or more delimited parkingspaces, if any (hereinafter, the undelimited parking spaces and thedelimited parking spaces will be collectively referred to as “parkingspaces”). Each undelimited parking space is a space that is notdelimited by the white lines or the like, has a size sufficient to parkthe vehicle, and is available (namely, there is no obstacle therein).Each delimited parking space is a space that is delimited by the whitelines or the like, has a size sufficient to park the vehicle, and isavailable (namely, another vehicle (vehicle other than the own vehicle)is not parked).

Next, the action plan unit 43 executes a trajectory calculation process(step ST2) to calculate a trajectory of the vehicle from a currentposition of the vehicle to each extracted parking space. In a case wherethe trajectory of the vehicle can be calculated for a certain parkingspace, the action plan unit 43 sets the parking space as a parkingposition candidate where the vehicle can be parked, and make the touchpanel 32 display the parking position candidate on the screen (theparking search screen). In a case where the trajectory of the vehiclecannot be calculated due to the presence of the obstacle, the actionplan unit 43 does not set the parking space as a parking positioncandidate and does not make the touch panel 32 display the parking spaceon the screen. When the action plan unit 43 sets multiple parkingposition candidates (namely, multiple parking places for which thetrajectory of the vehicle can be calculated), the action plan unit 43makes the touch panel 32 display these parking position candidates.

Next, the action plan unit 43 executes a target parking positionreception process (step ST3) to receive a selection operation performedby the occupant to select the target parking position, which is aparking position where the occupant wants to park the vehicle, and isselected from the one or more parking position candidates displayed onthe touch panel 32. More specifically, the action plan unit 43 makes thetouch panel 32 display the look-down image and the bird's-eye image inthe traveling direction on the parking search screen shown in FIG. 3A.When the action plan unit 43 acquires at least one parking positioncandidate, the action plan unit 43 makes the touch panel 32 display aframe that indicates the parking position candidate and an icon thatcorresponds to the frame in at least one of the look-down image and thebird's-eye image (in the look-down image in FIG. 3A) in an overlappingmanner. The icon consists of a symbol indicating the parking positioncandidate (see “P” in FIG. 3A). Also, the action plan unit 43 makes thetouch panel 32 display the parking search screen including anotification that instructs the driver to stop the vehicle and selectthe target parking position, so that the touch panel 32 receives theselection operation of the target parking position. The selectionoperation of the target parking position may be performed via the touchpanel 32, or may be performed via the selection input member 35.

After the vehicle is stopped and the target parking position is selectedby the driver, the action plan unit 43 makes the touch panel 32 switchthe screen from the parking search screen to the parking screen. Asshown in FIG. 3B, the parking screen is a screen in which an image inthe traveling direction of the vehicle (hereinafter referred to as“traveling direction image”) is displayed on the left half of the touchpanel 32 and the look-down image including the vehicle and itssurrounding area is displayed on the right half thereof. At this time,the action plan unit 43 may make the touch panel 32 display a thickframe that indicates the target parking position selected from theparking position candidates and an icon that corresponds to the thickframe such that the thick frame and the icon overlap with the look-downimage. This icon consists of a symbol indicating the target parkingposition, and is shown in a color different from the symbol indicatingthe parking position candidate.

After the target parking position is selected and the screen of thetouch panel 32 is switched to the parking screen, the action plan unit43 executes a driving process (step ST4) to make the vehicle travelalong the calculated trajectory. At this time, the action plan unit 43controls the vehicle based on the position of the vehicle acquired bythe GPS receiving unit 20 and the signals from the external cameras 19,the vehicle sensor 8, and the like so that the vehicle travels along thecalculated trajectory. At this time, the action plan unit 43 controlsthe powertrain 4, the brake device 5, and the steering device 6 so as toexecute a switching operation for switching the traveling direction ofthe vehicle (a reversing operation for reversing the traveling directionof the vehicle). The switching operation may be executed repeatedly, ormay be executed only once.

During the driving process, the action plan unit 43 may acquire thetraveling direction image from the external cameras 19 and make thetouch panel 32 display the acquired traveling direction image on theleft half thereof. For example, as shown in FIG. 3B, when the vehicle ismoving backward, the action plan unit 43 may make the touch panel 32display an image to the rear of the vehicle captured by the externalcameras 19 on the left half thereof. While the action plan unit 43 isexecuting the driving process, the surrounding image of the vehicle (theown vehicle) in the look-down image displayed on the right half of thetouch panel 32 changes along with the movement of the vehicle. When thevehicle reaches the target parking position, the action plan unit 43stops the vehicle and ends the driving process.

When the driving process ends, the action plan unit 43 executes aparking process (step ST5). In the parking process, the action plan unit43 first drives the shift actuator 17 to set the shift position (shiftrange) to a parking position (parking range). Thereafter, the actionplan unit 43 drives the parking brake device, and makes the touch panel32 display a pop-up window (see FIG. 3C) indicating that the automaticparking of the vehicle has been completed. The pop-up window may bedisplayed on the screen of the touch panel 32 for a prescribed period.Thereafter, the action plan unit 43 may make the touch panel 32 switchthe screen to an operation screen of the navigation device 10 or a mapscreen.

In the parking process, there may be a case where the shift positioncannot be changed to the parking position because of an abnormality ofthe shift actuator 17 or a case where the parking brake device cannot bedriven because of an abnormality of the parking brake device. In thesecases, the action plan unit 43 may make the touch panel 32 display thecause of the abnormality on the screen thereof

<The Driving Process>

Next, with reference to FIG. 4 and FIGS. 5A to 5C, the driving process(step ST4) of the above-mentioned automatic parking process will befurther described.

With reference to FIG. 4, when the driving process is started, theautomatic parking is also started (step ST11). When the automaticparking is started in this way, the action plan unit 43 causes thevehicle to start traveling along a first target route. The first targetroute is a route (trajectory) from a start position of the automaticparking to the target position, and is calculated so as to avoid theobstacle detected by the external environment sensor 7. Further, whenthe automatic parking is started as described above, the action planunit 43 causes the touch panel 32 to display an image (hereinafterreferred to as “the traveling direction image”) in the travelingdirection of the vehicle.

Next, the external environment recognizing unit 41 determines whetherthe obstacle is present on the first target route (step ST12). Forexample, in a case where the external environment sensor 7 detects theobstacle on the first target route, the external environment recognizingunit 41 determines that the obstacle is present on the first targetroute. On the other hand, in a case where the external environmentsensor 7 does not detect the obstacle on the first target route, theexternal environment recognizing unit 41 determines that the obstacle isnot present on the first target route. Incidentally, the determinationin step ST12 becomes “No” except for a case where a specific obstacle(for example, an obstacle that has not been present on the first targetroute at the calculation of the first target route or an obstacle thathas not been detected by the external environment sensor 7 at thecalculation of the first target route) is present.

In a case where the determination in step ST12 is “No” (in a case wherethe obstacle is not present on the first target route), the externalenvironment recognizing unit 41 repeats the determination in step ST12while the vehicle keeps on traveling along the first target route.Incidentally, in a case where the vehicle keeps on traveling along thefirst target route in this way and consequently reaches the targetposition, the driving process ends.

On the other hand, in a case where the determination in step ST12 is Yes(in a case where the obstacle is present on the first target route), theexternal environment recognizing unit 41 determines whether the vehiclehas approached the obstacle on the first target route (step ST13). Forexample, while the distance between the vehicle and the obstacledetected by the external environment sensor 7 is equal to or more than aprescribed threshold, the external environment recognizing unit 41determines that the vehicle has not approached the obstacle. On theother hand, in a case where the distance between the vehicle and theobstacle detected by the external environment sensor 7 becomes less thanthe above threshold, the external environment recognizing unit 41determines that the vehicle has approached the obstacle.

In a case where the determination in step ST13 is “No” (in a case wherethe vehicle has not approached the obstacle on the first target route),the external environment recognizing unit 41 repeats the determinationin step ST13 while the vehicle keeps on traveling along the first targetroute. In another embodiment, in a case where the determination in stepST13 is “No”, the external environment recognizing unit 41 may againdetermine whether the obstacle is present on the first target route(step ST12).

On the other hand, in a case where the determination in step ST13 is“Yes” (in a case where the vehicle has approached the obstacle on thefirst target route), the action plan unit 43 suspends the automaticparking and causes the vehicle to stop traveling along the first targetroute (step ST14). At this time, the action plan unit 43 may drive theshift actuator 17 to shift the shift position to the parking position,or may drive the parking brake device (not shown).

Next, the action plan unit 43 tries to calculate a second target route,which is different from the first target route (step ST15). The secondtarget route is a route (trajectory) to the target position from aposition where the vehicle stops traveling along the first target routein step ST14, and is calculated so as to avoid the obstacle on the firsttarget route detected by the external environment sensor 7 in steps ST12and ST13. For example, in a case where the action plan unit 43 cancalculate the second target route whose length is equal to or less thana prescribed reference distance, the action plan unit 43 succeeds incalculating the second target route. On the other hand, in a case whereit is physically impossible for the action plan unit 43 to calculate thesecond target route (for example, in a case where the obstacle isblocking the entrance to the target position) or in a case where theaction plan unit 43 can only calculate the second target route whoselength is more than the above reference distance, the action plan unit43 fails to calculate the second target route.

In a case where the determination in step ST15 is “No” (in a case wherethe action plan unit 43 fails to calculate the second target route), theaction plan unit 43 executes a display process (step ST16). The detailsof the display process will be described later.

On the other hand, in a case where the determination in step ST15 is“Yes” (in a case where the action plan unit 43 succeeds in calculatingthe second target route), the action plan unit 43 causes the touch panel32 to switch the traveling direction image (step ST17). For example, ina case where the vehicle has been moving forward immediately before thevehicle stops traveling along the first target route, the travelingdirection image is switched from an image in front of the vehicle to animage behind the vehicle. On the other hand, in a case where the vehiclehas been moving backward immediately before the vehicle stops travelingalong the first target route, the traveling direction image is switchedfrom the image behind the vehicle to the image in front of the vehicle.Namely, the action plan unit 43 causes the touch panel 32 to display thetraveling direction image in the direction opposite to the travelingdirection of the vehicle immediately before the vehicle stops travelingalong the first target route.

Next, the action plan unit 43 determines whether the driver (an exampleof the user) performs the brake operation of the vehicle (step ST18).For example, in a case where the pressing amount of the brake pedal 24detected by the brake sensor 27 is equal to or more than a prescribedreference amount, the action plan unit 43 determines that the driverperforms the brake operation of the vehicle. On the other hand, in acase where the pressing amount of the brake pedal 24 detected by thebrake sensor 27 is less than the reference amount, the action plan unit43 determines that the driver does not perform the brake operation ofthe vehicle.

In a case where the determination in step ST18 is “No” (in a case wherethe driver does not perform the brake operation of the vehicle), theaction plan unit 43 causes the touch panel 32 to display a promotionscreen 51 shown in FIG. 5A (step ST19). The promotion screen 51 is ascreen including a message promoting the brake operation of the vehicle.When step ST19 ends, the action plan unit 43 again determines whetherthe driver performs the brake operation of the vehicle while keeping oncausing the touch panel 32 to display the promotion screen 51 (stepST18).

On the other hand, in a case where the determination in step ST18 is“Yes” (in a case where the driver performs the brake operation of thevehicle), the action plan unit 43 causes the touch panel 32 to display aresumption notification screen 52 shown in FIG. 5B (step ST20). Theresumption notification screen 52 is a screen including a messagenotifying the driver that the automatic parking will be resumed when thedriver stops performing the brake operation of the vehicle.

Next, the action plan unit 43 determines whether the driver stopsperforming the brake operation of the vehicle (step ST21). For example,in a case where the pressing amount of the brake pedal 24 detected bythe brake sensor 27 becomes less than the reference amount, the actionplan unit 43 determines that the driver stops performing the brakeoperation of the vehicle. On the other hand, in a case where thepressing amount of the brake pedal 24 detected by the brake sensor 27 isstill equal to or more than the above reference amount, the action planunit 43 determines that the driver does not stop performing the brakeoperation of the vehicle.

In a case where the determination in step ST21 is “No” (in a case wherethe driver does not stop performing the brake operation of the vehicle),the action plan unit 43 repeats the determination in step ST21 while thevehicle is stopped.

On the other hand, in a case where the determination in step ST21 is“Yes” (in a case where the driver stops performing the brake operationof the vehicle), the automatic parking is resumed (step ST22). When theautomatic parking is resumed in this way, the action plan unit 43 causesthe vehicle to start traveling along the second target route. When thevehicle starts traveling along the second target route in this way, thetraveling direction of the vehicle is switched in order to move thevehicle away from obstacle on the first target route. In a case wherethe vehicle keeps on traveling along the second target route andconsequently reaches the target position, the driving process ends.

<The Display Process>

Next, the display process (step ST16) in the above driving process willbe further described with reference to FIGS. 5A to 5C and FIG. 6.

With reference to FIG. 6, when the display process is started, theaction plan unit 43 determines whether a period (hereinafter referred toas “the non-performance period”) during which the driver does notperform the brake operation of the vehicle continues for a prescribedperiod T or more (step ST31). For example, in a case where the pressingamount of the brake pedal 24 detected by the brake sensor 27continuously falls below the reference amount for the prescribed periodT or more, the action plan unit 43 determines that the non-performanceperiod continues for the prescribed period T or more. On the other hand,in a case where the pressing amount of the brake pedal 24 detected bythe brake sensor 27 becomes equal to or more than the above referenceamount within the prescribed period T, the action plan unit 43determines that the non-performance period does not continue for theprescribed period T or more.

In a case where the determination in step ST31 is “Yes” (in a case wherethe non-performance period continues for the prescribed period T ormore), the action plan unit 43 causes the touch panel 32 to display thepromotion screen 51 (an example of a promotion notification; see FIG.5A) as a notification about the automatic parking (step ST32). Asdescribed above, the promotion screen 51 is a screen including a messagepromoting the brake operation of the vehicle.

Next, the action plan unit 43 determines whether the driver performs thebrake operation of the vehicle (step ST33) in the same way as step ST18described above.

In a case where the determination in step ST33 is “No” (in a case wherethe driver does not perform the brake operation of the vehicle), theaction plan unit 43 repeats step ST32 and step ST33. Namely, the actionplan unit 43 repeats the determination as to whether the driver performsthe brake operation of the vehicle while causing the touch panel 32 todisplay the promotion screen 51.

On the other hand, in a case where the determination in step ST33 is“Yes” (in a case where the driver performs the brake operation of thevehicle), the action plan unit 43 causes the touch panel 32 to display aresumption selection screen 53 (an example of a resumption selectionnotification; see FIG. 5C) (step ST34). The resumption selection screen53 is a screen on which the driver can select the resumption of theautomatic parking.

Next, the action plan unit 43 determines whether an operation(hereinafter referred to as “the resumption selection operation”) forselecting the resumption of the automatic parking is performed on theresumption selection screen 53 (step ST35). For example, in a case wherea button (“Yes” in FIG. 5C) for selecting the resumption of theautomatic parking is pressed on the resumption selection screen 53, theaction plan unit 43 determines that the resumption selection operationis performed.

In a case where the determination in step ST35 is “No” (in a case wherethe resumption selection operation is not performed on the resumptionselection screen 53), the action plan unit 43 repeats step ST34 and stepST35. Namely, the action plan unit 43 repeatedly determines whether theresumption selection operation is performed while causing the touchpanel 32 to display the resumption selection screen 53. Incidentally, ina case where a button (“No” in FIG. 5C) for not selecting the resumptionof the automatic parking is pressed on the resumption selection screen53, the action plan unit 43 may cancel (end) the automatic parking.

On the other hand, in a case where the determination in step ST35 is“Yes” (in a case where the resumption selection operation is performedon the resumption selection screen 53), the action plan unit 43determines whether the driver stops performing the brake operation ofthe vehicle (step ST36) in the same way as step ST21 described above.

In a case where the determination in step ST36 is “No” (in a case wherethe driver does not stop performing the brake operation of the vehicle),the action plan unit 43 repeats the determination in step ST36.

On the other hand, in a case where the determination in step ST36 is“Yes” (in a case where the driver stops performing the brake operationof the vehicle), the automatic parking is resumed (step ST37). In a casewhere the automatic parking is resumed in this way and the obstacle isno longer present on the first target route, the action plan unit 43resumes traveling of the vehicle along the first target route. In a casewhere the vehicle keeps on traveling along the first target route andconsequently reaches the target position, the display process ends.Accordingly, the driving process also ends.

By the way, even if the automatic parking is resumed in step ST37, theobstacle may still be present on the first target route. In such a case,the action plan unit 43 stands by in a state where the vehicle stopstraveling without causing the vehicle to start traveling along the firsttarget route. The driver can cancel the automatic parking at any time byperforming an operation for selecting the cancelation (end) of theautomatic parking on the touch panel 32 or the parking main switch 34.

Returning to step ST31 of the display process, in a case where thedetermination in step ST31 is “No” (in a case where the non-performanceperiod does not continue for the prescribed period T or more), theexternal environment recognizing unit 41 determines whether the obstacleis present on the first target route (step ST38) in the same way as stepST12 described above.

In a case where the determination in step ST38 is “Yes” (in a case wherethe obstacle is present on the first target route), the action plan unit43 again determines whether the non-performance period continues for theprescribed period T or more (step ST31). Incidentally, even if theexternal environment sensor 7 keeps on detecting the obstacle on thefirst target route and thus the determination in step ST38 becomes“Yes”, the action plan unit 43 prohibits a notification about thepresence of the obstacle on the first target route (an example of anotification about the automatic parking) while the determination instep ST31 remains “No” (namely, while the driver performs the brakeoperation of the vehicle). Namely, the action plan unit 43 does notcause the touch panel 32 to display a message notifying the presence ofthe obstacle on the first target route. Also, the action plan unit 43does not cause the sound generating device 33 to generate voice guidancenotifying the presence of the obstacle on the first target route.

On the other hand, in a case where the determination in step ST38 is“No” (in a case where the obstacle is not present on the first targetroute), the action plan unit 43 determines whether the driver stopsperforming the brake operation of the vehicle (step ST36). As describedabove, in a case where the determination in step ST36 is “No”, theaction plan unit 43 repeats the determination in step ST36. On the otherhand, in a case where the determination in step ST36 becomes “Yes”, theautomatic parking is resumed (step ST37).

<Effect>

As described above, upon succeeding in calculating the second targetroute, the action plan unit 43 causes the touch panel 32 to display thetraveling direction image corresponding to the second target route (stepST17). On the other hand, upon failing to calculate the second targetroute, the action plan unit 43 causes the touch panel 32 to display thepromotion screen 51 on condition that the non-performance periodcontinues for the prescribed period T or more (steps ST31 and ST32).Thus, the touch panel 32 can selectively display either the travelingdirection image or the promotion screen 51 depending on the success orfailure of the calculation of the second target route. Accordingly, itis possible to appropriately notify the user of the behavior of thevehicle.

Also, as described above, when the vehicle starts traveling along thesecond target route after stopping traveling along the first targetroute, the traveling direction of the vehicle is switched in order tomove the vehicle away from the obstacle on the first target route. Inlight of such a situation, upon succeeding in calculating the secondtarget route, the action plan unit 43 causes the touch panel 32 todisplay the traveling direction image in the direction opposite to thetraveling direction of the vehicle immediately before the vehicle stopstraveling along the first target route (step ST17). Thus, the touchpanel 32 can display an appropriate traveling direction image inconsideration of the above switch in the traveling direction of thevehicle. Accordingly, it is possible to prompt the user to monitor thesurroundings of the vehicle, and to improve the safety of the vehicleaccordingly.

Also, upon succeeding in calculating the second target route, the actionplan unit 43 causes the vehicle to start traveling along the secondtarget route at least on condition that the user performs the brakeoperation of the vehicle (steps ST18 and ST22). Thus, it is possible tocause the vehicle to start traveling along the second target route afterthe user performs the brake operation of the vehicle. Accordingly, theuser can easily predict that the vehicle will travel along the secondtarget route.

Also, upon failing to calculate the second target route, the action planunit 43 makes a determination as to a performance state of the brakeoperation of the vehicle by the user (step ST31). Thus, the action planunit 43 can perform appropriate control according to the performancestate of the brake operation of the vehicle by the user. Accordingly, itis possible to improve the safety of the vehicle.

Also, upon failing to calculate the second target route, the action planunit 43 prohibits the notification about the presence of the obstacle onthe first target route while the user is performing the brake operationof the vehicle (steps ST31 and ST38). Thus, it is possible to preventthe notification about the presence of the obstacle on the first targetroute from being given even though the user is aware of the obstacle onthe first target route, thereby preventing the user from being annoyed.

Also, in a case where the non-performance period continues for theprescribed period T or more, the user may not be monitoring thesurroundings of the vehicle even though the obstacle is present on thefirst target route. In light of such a situation, in a case where thenon-performance period continues for the prescribed period T or more,the action plan unit 43 causes the touch panel 32 to display thepromotion screen 51 (steps ST31 and ST32). Thus, it is possible toimprove the safety of the vehicle. Further, the promotion screen 51 isdisplayed on condition that the non-performance period continues for theprescribed period T or more (namely, the user does not perform the brakeoperation for the prescribed period T or more), thereby preventing thepromotion screen 51 from being displayed at an excessively early timingafter the user stops performing the brake operation. Accordingly, it ispossible to more effectively prevent the user from being annoyed.

Further, in a case where the user performs the brake operation of thevehicle in response to the promotion screen 51, the action plan unit 43causes the touch panel 32 to display the resumption selection screen 53(steps ST32 and ST34). Accordingly, it is possible to resume theautomatic parking based on the user's intention, thereby improving thesafety of the vehicle.

Further, in a case where the action plan unit 43 determines that thenon-performance period does not continue for the prescribed period T ormore and the external environment sensor 7 no longer detects theobstacle on the first target route, the action plan unit 43 resumes theautomatic parking on condition that the user stops performing the brakeoperation of the vehicle (steps ST31 and ST36 to ST38). Thus, it ispossible to resume the automatic parking without resetting the targetroute, and to improve the convenience of the user accordingly.

<Modification>

In the present embodiment, upon succeeding in calculating the secondtarget route, the action plan unit 43 causes the vehicle to starttraveling along the second target route on condition that the userperforms the brake operation of the vehicle (see FIG. 4). On the otherhand, in another embodiment, upon succeeding in calculating the secondtarget route, the action plan unit 43 may cause the vehicle to starttraveling along the second target route regardless of whether the userhas performed the brake operation of the vehicle (see FIG. 7). Namely,in another embodiment, the action plan unit 43 may proceed to step ST21after the above-mentioned step ST17 without performing steps ST18 toST20. Thus, it is possible to cause the vehicle to start traveling alongthe second target route without causing the user to perform the brakeoperation of the vehicle. Accordingly, it is possible to improve theconvenience of the user.

In the present embodiment, the touch panel 32 mounted on the vehicle iscited as an example of the display unit. In another embodiment, acommunication device (for example, a smartphone, a tablet PC, a mobilephone, a PDA, or the like) configured to communicate with the vehiclemay be cited as an example of the display unit. Namely, the display unitis not necessarily mounted on the vehicle.

In the present embodiment, the driver is cited as an example of theuser. On the other hand, in another embodiment, the occupant other thanthe driver may be cited as an example of the user, or a person otherthan the occupant (a person outside the vehicle) may be cited as anexample of the user.

Concrete embodiments of the present invention have been described in theforegoing, but the present invention should not be limited by theforegoing embodiments and various modifications and alterations arepossible within the scope of the present invention.

1. A parking assist system configured to execute automatic parking forautonomously moving a vehicle to a target position, the parking assistsystem comprising: an acquiring unit configured to acquire surroundinginformation about surroundings of the vehicle; a display unit configuredto display the surrounding information acquired by the acquiring unit;and a control unit configured to calculate a first target route to thetarget position based on the surrounding information acquired by theacquiring unit and to cause the vehicle to travel along the first targetroute, wherein in a case where the acquiring unit acquires informationabout an obstacle on the first target route during traveling of thevehicle along the first target route and thus the vehicle stopstraveling along the first target route, the control unit tries tocalculate a second target route to the target position from a positionwhere the vehicle stops traveling along the first target route, uponsucceeding in calculating the second target route, the control unitcauses the display unit to display the surrounding informationcorresponding to the second target route, and upon failing to calculatethe second target route, the control unit causes the display unit todisplay a notification about an operation method of the vehicle.
 2. Theparking assist system according to claim 1, wherein the display unit isconfigured to display a traveling direction image as the surroundinginformation, the traveling direction image being an image in a travelingdirection of the vehicle, and upon succeeding in calculating the secondtarget route, the control unit causes the display unit to display thetraveling direction image in a direction opposite to the travelingdirection of the vehicle immediately before the vehicle stops travelingalong the first target route.
 3. The parking assist system according toclaim 1, wherein upon succeeding in calculating the second target route,the control unit causes the vehicle to start traveling along the secondtarget route regardless of whether a user has performed a brakeoperation of the vehicle.
 4. The parking assist system according toclaim 1, wherein upon succeeding in calculating the second target route,the control unit causes the vehicle to start traveling along the secondtarget route at least on condition that a user performs a brakeoperation of the vehicle.
 5. The parking assist system according toclaim 1, wherein upon failing to calculate the second target route, thecontrol unit makes a determination as to a performance state of a brakeoperation of the vehicle by a user.
 6. The parking assist systemaccording to claim 5, wherein upon failing to calculate the secondtarget route, the control unit causes the display unit to display apromotion notification as the notification about the operation method ofthe vehicle, the promotion notification promoting the brake operation ofthe vehicle.
 7. The parking assist system according to claim 6, whereinupon failing to calculate the second target route, the control unitdetermines whether a non-performance period during which the user doesnot perform the brake operation of the vehicle continues for aprescribed period or more, and upon determining that the non-performanceperiod continues for the prescribed period or more, the control unitcauses the display unit to display the promotion notification.
 8. Theparking assist system according to claim 6, wherein in a case where theuser performs the brake operation of the vehicle in response to thepromotion notification, the control unit causes the display unit todisplay a resumption selection notification in which the user can selectresumption of the automatic parking.
 9. The parking assist systemaccording to claim 1, wherein upon failing to calculate the secondtarget route, the control unit determines whether a non-performanceperiod during which a user does not perform a brake operation of thevehicle continues for a prescribed period or more, and in a case wherethe control unit determines that the non-performance period does notcontinue for the prescribed period or more and the acquiring unit stopsacquiring the information about the obstacle on the first target route,the control unit resumes the automatic parking at least on conditionthat the user stops performing the brake operation of the vehicle.